Slotted abrasive wheel



Patented Aug. 4,v 19336 UNITED STATES vzii-49,874

PATENT oFElcE '2.1149314 l sLo'rTED ABaAsIvE WHEEL Harley E. Sherk, Miami, Fla., assignor to Miami Abrasive Products, Inc., Miami, Fla., a corpo- -ration of Florida.'

Application August 2l, 1933, Serial No. 686,0'll a claim. (orsi-zoe) hanced by the provision of spaced slots inthe grinding surface of the wheel to, form a plurality of grinding surfaces in spaced relation from each other. The slots create non-grinding areas adjacent the grinding surfaces of the wheel and thereby greatly reduce friction and heating during the grinding operations 'since :the material being ground is not subjected to a steady and constant grinding. In addition, the slots carry 2d air which aids in cooling the material .being ground.

The sharp edges formed in the grinding face by the slots impart a milling or cutting action as the material being ground passes over the slots and contacts these edges. This action coupled with the usual grinding action o f the grinding faces forms an abrasive wheel with high capacity.

The slots also-act to eliminate abraded parti- 'cles which normally are withheld in the abrasive grinding surface and in addition, by effecting an intermittent grinding operation do not permit the. abraded particles to form streaks around the wheel.

It is', therefore, an object.of this invention to provide abrasive grinding wheels having alternate areas of nongrinding spaces and grinding v surfaces. Y .E

Another object of this invention is to provide a slotted abrasive wheel.

Another object of this invention is to improve the grinding eiilciency of abrasive wheels by forming the wheels with alternately disposed cutting edges adjacent to the grinding surfaces.

Another object of this invention is to provide a self-cleaning abrasive wheel.

Another object of this invention is to form. abrasive wheels with intermittent grinding sur- A'faces to reduce friction and eliminate overheating of the material being ground.

abrasive Wheel accordingito this invention in' which the grinding surfaces are on the periphery of the wheel.

60. Figure 2 is an end elevational view, partly in capacity of abrasive wheels can be greatly encross section, rof the grinding wheel shown in- Figixre 1 taken substantially along the line' II- Figure 3 is a front side elevational view of a' hollow cylinder form Vof abrasive wheel slotted 5 on a flat face according to this invention to form a fiat slotted grinding surface. j

Figure 4 is a view, partly in cross-section, taken substantially along the line IV-IV of Figure 3. i 10 Figures 5 to 8 are plan views of grinding surfaces according to this invention showing alterna tive forms of slot designs in the surfaces.

As shown on the drawing:

In Figures l and 2,' the reference numeral in ,l

indicates an. abrasive wheel formed from'any abrasive material, such as silicon carbide, emery, carborundum, glass, or Aany natural or artificialv abrasive or combination thereof. The abrasive material may be in grain form and molded in 20' Aany bonding material, such as bakelite. Since this invention deals with the formation of slots or alternatelydisposed non-grinding spaces adjacent the grinding surfaces of abrasive wheels, it should be understood that any materials nor- 25 mally used for forming abrasive wheels can be used.

The abrasive wheel I0 is provided with an opening II in the center thereof for receiving a bushing I2 which permits the mounting of 30 the wheel onto a driven shaft. 'Ihe bushing I2 is usually molded into the opening II to form an integral connection between the grinding wheel and the driven shaft.

The periphery of the wheel I0 is provided with 35 a plurality of parallel slots I3 in spaced relation from each other extending transversely across the periphery. 'I'he slots I3 extend into the wheel for a considerable distance below the outside periphery but, as may be readily appreciated, 40 the depth of the slots is limited `by the strength of the abrasive material forming the wheel, it being evident that a relatively soft material would crumble and break off. If a soft material is used. the slots are relatively shallow. 45

The slots I3 form radially extending teeth or intermittent portions I4 around the periphery of the wheel. Each tooth I4 has a grinding surface I5 on its outer periphery. In addition to the grinding actionof the surfaces' I5, the sharp 50 edges of the teeth permit a milling or cutting action during the grinding operation.

As shown in Figures 3 .and 4, the reference 4 numeral 20 indicates a hollow cylindrical form of grinding wheel provided with slots 2| in aiiat 55 face of the wheel so as to form intermittent grindingportions 22 in addition to a grinding surface 23 on the periphery of the wheel. The slots 2l have the same cooling and cleaning action on the dat grinding surfaces 22 as the slots 60 I3 have on the peripheral grinding surfaces I5 shown in Figures l and 2.

As shownin Figures 3 and '4,' the abrasive wheel is of a hollow cylindrical form with an opening in the center for receiving a bushing 24r which is integrally bonded to the abrasive material. e As shown in Figure 4, the bushing 24 terminates short of the flat grinding surfaces 22 so as not to interfere with the grinding operation. A driven shaft may be inserted in the hollow bushing 24. The bushing 24 is detachably secured to the shaft in any suitable manner.

The grinding surfaces shown in Figure 5 are formed in a checkerboard arrangement in which the slots adjacent the grinding surfaces are rectangular or cube-shaped and do not extend across the entire fiat surface or prriphery of the wheel.

This design may sometimes be desirable to form a more solid Wheel.

As shown, the grinding surfaces 30 are in the form of rectangular portions each of which is separated from a corresponding rectangular portion in the same row by a slot 3|, which touches the corners of twogrinding portions in an adjacent row since the slots 3| extend only half-way across the grinding Wheel. The slots 3| and the grinding surface portions 30 are of substantially the same width.

In Figure 6, a grinding surface 40 is provided with transversely extending slots 4| which are offset at tite center of the grinding wheel and extend to the opposite side of the wheel in an oiset position. y This design effects a very strong construction since the staggered arrangement of the slots distributes the stress on any cutting edge of a grinding portion over a greater area. The slots 4| are approximately half the width of the grinding portions 40 and extend about half way through the thickness of the wheel. This form of design may be referred to as a staggered slotted abrasive wheel.

In Figure 7, diagonal grinding surfaces 50 are formed by diagonal slots 5| extending acrossthe width of the wheel. The'slots 5| are substantially identical with the slots I3 shown in Figure 1 or with the slots 2| shown in Figure 3 except that they extend diagonally across the grinding face instead of transversely across the face.

In Figure 8, slots 6| are formed in V-shape to form V-shaped grinding portions 60. The points of the V-portions 60 are preferably at the center of the grinding face. 'I'he V-portions have desirable characteristics in some grinding operations, and act as plows for throwing the abraded particles outwardly from the material being ground.

From the above description, it is evident that this invention includes grinding wheels having slots in their grinding surfaces which may be of many different forms or designs, such as the` straight transverse slots shown in Figures 1 to 4, the checkered slot arrangement shown in Figure 5, the staggered slot arrangement shown in Fig-V ure 6, the diagonal slots shown in Figure '7 or the V-shaped slots shown in Figure 8. The provision of slots, such as are shown, eliminates `a large percentage of friction during the grinding operation and when formed on peripheral grinding faces creates a milling action in addition to the usual straight grinding operation because of the sharp edges which are formed adjacent the slots.

When the abrasive wheel is revolving during the grinding operatiomair is carried by the slots and directed against the material being ground.

'Ihe air has able. In the normal grinding operations on abrasive wheels there is a lstrong tendency for the abraded particles to remain on the surface of the wheel. Often, these particles are reground between the material being groundand the wheel thereby ca using scratches and tending to glaze the wheel and retard the cutting. The slotted portions on wheels of this invention act as cleaners and cause the removal of the abraded particles since these particles are naturally thrown into the slots from whichthey are removed by the velocity of the Wheel.

'I'he slotted grinding wheels may be made in any desired size. I have fonned some ofthe slotted wheels in accordance with this invention of a size small enough for dentists to use in grinding teeth. 'Ihe cooling action created by the slots a cooling action and is highly desireliminates much of the heat that is generated 20- during the grinding operation with the present type of dentists wheel. Furthermore, the slots permit the wheel to remain in true shape for a longer period of time.

Slotted wheels of my invention are particularly 25 adapted for shoe making and shoe repair work because abraded leather particles are readily removed from the wheel by the slots.

It should be understood that the abrasive Wheels of this invention have pre-formed slots 30 therein which are as deep as the strength of the.

molding material bonding the abrasive particles together will permit. 'I'hese pre-formed slots are 'not to be confused with burred surfaces such as are cut into grinding wheels to sharpen the 35 same after use.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from'the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than is Anecessitated-by the prior art.

I claim as my invention:

1. An abrasive wheel comprising a cylindrical member having a flat face and an aperture extending therethrough, staggeredl grinding Asurfaces formed inv said face by slots extending radially from the aperture half-way to the outside periphery of the cylinder and offset at the halfway mark to extend to the periphery in an offset portion. e

2. An abrasive Wheel having a peripheral grinding surface. said 'grinding surface being divided into a plurality of rectangular surfaces in spaced relation from each other, said surfaces being in staggered relation-with rectangular slots extending transversely therebetween from one face'of the wheel to the middle of the periphery thereof and being offset 'at the middle of the periphery 00 having anannular cross section in* a plane at 65 right angles to its axis of rotation, a plurality of teeth extending outwardly vfrom the body portion and presenting at their outer ends grinding surfaces in staggered relation, said teeth being separated in a circumferential direction by trans- 70 verse slots having portions oifset in a direction circumferentially .of said wheel.

HARLEY E. SHERK. 

